Embodiments of the inventive concept relate to an encoder. In particular, the inventive concepts relate to an encoder that uses sign data hiding to enable the adjustment of a value of a coefficient included in an adjustment target coefficient group, defined in each coefficient group.
When image data is encoded, the image data can be compressed by removing spatial redundancy or temporal redundancy from the image data. A spatial transform may be performed in order to remove the spatial redundancy. Predicative coding may be performed using a frame preceding a currently encoded frame and/or a frame succeeding the currently encoded frame to remove the temporal redundancy. Apart from the approach for removing the spatial or temporal redundancy from the image data, other various approaches for compressing the image data have been developed.